The guy from eBay got back to me and he's got the WS2811 in DIP and at a reasonable price ($0.60 each in small quantities...)

That sounds quite expensive per-LED but they can really save a lot of work/wires, especially if the LEDs are far apart. You only need three wires between each RGB LED to make it work and the datasheet says you can have up to 20 meters between each one.

Plus ... you can drive any number of LEDs with only one Arduino pin.

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)